Three-position valve for aerosol container having a chamber with spaced inlets from container interior



Nov. 8, 1966 M. E. WHITMORE 3,283,962

THREE-POSITION VALVE FOR AEROSOL CONTAINER HAVING A CHAMBER WITH SPACEDINLETS FROM CONTAINER INTERIOR Filed Sept. 9, 1964 2 Sheets-Sheet 1 1 ,146 IO I 45 INVENTOR. MAX E. WH/ TMORE ATTORNEYS Nov. 8, 1966 M. E.WHITMORE THREE-POSITION VALVE FOR AEROSOL CONTAINER HAVING A CHAMBERWITH SPACED INLETS FROM CONTAINER INTERIOR Filed Sept. 9, 1964 2Sheets-Sheet 2 Fig. 4

' INVENTOR. MAX E. WH/ TMORE ATTORNEYS.

United States Patent THREE-POSITION VALVE FOR AEROSOL CON- TAINER HAVINGA CHAMBER WllH SPACED INLETS FROM CONTAINER INTERIOR Max E. Whitmore,7585 Samuel Lord Drive, Chagrin Falls, Ohio Filed Sent. 9, 1964, Ser.No. 395.172 16 Claims. (Cl. 222402.18)

This invention relates generally to valve mechanisms of the type used inconjunction with pressurized containers, and more specifically to a newand improved dispensing valve which can be used when the container is inei ther an upright or inverted position and which is selfcleaning.

Prior to the invention described and claimed in my U.S. Patent No.3,049,271, issued August 14, 1962 for Valve Mechanisms for PressurizedCans, there was no dispensing valve which was both self-cleaning andcapable of being operated in either an upright or inverted position ofthe container. The invention disclosed in that patent provided such avalve mechanism. In general, the patented construction comprises a valvestem which is reciprocable in a hollow valve body having an upper inletopening communicating with the top of the can and a lower inlet openingcommunicating with the bottom of the can. The valve stem is movable froma closed position to first and second operative positions wherein theoutlet passage of the valve stem communicates with the upper and lowerinlet openings, respectively. An annular packing ring is mounted in theValve body around the stem to seal its inlet opening from the loweropening in the first position and from the upper opening in the secondposition.

The present invention contemplates new and useful improvements in adispensing valve of the type described. One important feature of theinvention resides in improved sealing structure which is effective toseal the inlet port of the valve stem from both inlet openings of thevalve body in a closed position of the stem and selectively to seal theinlet port from the inlet openings in the two operative positions of thestem.

With the resilient packing rings which have been used in the past, therehas been a tendency for the gaseous propellant to leak from thepressurized container around the stem in its closed position. Theconventional sealing ring arrangements also have been subject to wearduring use due to the manner in which the rings were flexed and/or thefriction of the valve stem so that the seals gradually lost theireffectiveness. The resulting loss of the propellant due to leakage fromthe can when it was not in use resulted in an insuflicient amount of thepropellant being available completely to expel all of the liquidproduct.

The structure provided by this invention effectively prevents leakage byforming a positive gas tight seal over the inlet port of the stem whenthe valve is closed. In addition, the preferred structure includes aradial flange on the valve stem which coacts with the valve body in aclosed position to assist in preventing leakage around the stern. Inthis manner, the inlet openings of the valve body are completely sealedoff from the valve stem inlet and from the part of the valve stemprojecting from the top of the body. The resulting sealing arrangementis I 3,283,962 Patented Nov. 8, I966 ice long-lived and will not loseits effectiveness in preventing gas leakage because of use.

Another important feature of the invention resides in a simplified,relatively inexpensive, and easily assembled valve construction.Heretofiore, many of the conventional valves have been complex,primarily because of the manner in which it was attempted to provide aseal around the stem. As a result, these prior structures have beendifiicult to assemble and were relatively expensive.

According to the present invention, there is provided a hollow valvebody having a first inlet opening communicating with the top of thecontainer and a second inlet opening communicating through a dip tubewith the bottom of the container. A valve stem having an out-let passagewith an inlet port and an outlet port is movable in the valve body froma closed position to a first operative position in which the first inletopening and the inlet port are in communication and to a secondoperative posit-ion in which the inlet port communicates with the secondinlet opening. To seal the valve, there is preferably provided a primaryseal member which coacts with the stem to form a gas-tight, positiveseal over the inlet port in the closed position. A radial flange on thestem is in Wiping engagement with the inside of the valve body and abutsthe primary seal member in the closed position. In this manner, thegaseous propellant is positively prevented from leaking around the valvestem and through its outlet passage.

A secondary seal member is located in the valve body and coacts with thestem to prevent the flow of fluid from the dip tube through the valvebody in the closed and first positions of the stem. In the preferredembodiment, the stem is formed with an elongated slot which serves toby-pass the secondary seal member in the second position of the valve,thereby allowing fluid to flow firorn the dip tube through the secondinlet opening and into the outlet or discharge passage of the stern.

Other features, advantages and a fuller understanding of the inventionwill be had by reference to the following detailed description and theaccompanying drawings.

In the drawings:

FIGURE 1 is a partially sectioned view of a pressurized containerembodying the preferred valve mechanism of this invention;

FIGURE 2 is an enlarged, vertical cross-sectional view of the valvemechanism in a closed position;

FIGURE 3 is a view similar to FIG. 2 showing the valve in anotheroperative position; and,

FIGURE 4 is another view similar to FIG. 2 showing the valve in a fullyopen position.

Referring now to the drawings, and more particularly to FIG. 1, thepreferred embodiment of the new valve is gene-rally indicated byreference numeral 10. The valve 10 is shown in conjunction with atypical pressurized container in the form of an aerosol can 11. The can11 may contain a liquid product 12 and a gaseous propellant orp-ressurizing element 13. The can 11 is illustrated in an uprightposition with the liquid 12 settled at the bottom of the can away fromthe valve 10 and with the gaseous propellant 13 surrounding the valve.

Referring now to FIG. 2, the valve mechanism 10 is shown to comprise avalve body 20 which may be crimped or otherwise secured in the top ofthe can 11. The valve body 20 is formed with a through axial bore 21which terminates at a lower inlet opening 22. A dip tube 23 is suitablyconnected to the lower end of the valve body 20 so that the opening 22is in communication with the bottom part of the container 11. The bore21 includes an intermediate co-unterbore 24 which terminates at ashoulder 25 and an enlarged upper end portion 26. As shown, the enlargedupper end portion 26- and the counterbore 24 are joined by an axiallyinwardly and downwardly sloping shoulder 27. The valve body 20 also hasa transverse inlet opening 28 which opens inwardly on the slopingshoulder 27 and is in communication with the top portion of the can 11.

A cap 34 having a center opening 35 is suitably secured to the upper endof the valve body 20 across the mouth of the enlarged end portion 26 ofthe bore 21. A primary sealing member 36 in the form of a ring ismounted against the cap 34 within the mouth of the bore portion 26. Theprimary sealing member 36 is preferably formed of a resilient material,such as a synthetic rubber or the like, and may be secured within agroove in the bottom surface of the cap 34. A secondary sealing member37 formed by a ring of plastic or other suitable material is mounted inthe bore 21 against the shoulder 25. The spaced sealing members 36, 37cooperate to define a fluid chamber or cavity 38 within the portions 24,26 of the bore 21.

A reciprocable valve stem 45 extends into the bore 21 and has asubstantially fluid-tight running fit through the opening 35 of the cap34 and the sealing rings 36, 37. As shown, the upper end portion of thevalve stem 45 is provided with an axial outlet passage 46 which extendsfrom an inlet port 47 formed through the side wall of the stem to adischarge or outlet port. 48 which vents to the outside of the can 11.The lower end portion of the valve stem 45 is provided with an inletpassage 49. According to the illustrated construction, the inlet passage49 is formed by an elongated slot cut in the side wall of the valvestem.

The valve stem 45 also includes a radial flange 50 or desk which isadjacent the upper end of the slot 49 and below the inlet port 47. Theflange 50 may be formed integrally with the stem or it may be a separatemember which is suitably secured thereto. The flange 50 is formed with apassage 51 which is located outwardly of the valve stem and extendsbetween the upper and lower surfaces of the flange so as to permit fluidin the chamber 38 to flow past the flange. In the preferred embodiment,the outer peripheral surface of the flange 50 is in wiping engagementwith the wall surface of the enlarged bore portion 26 and the lowerperipheral edge 52 of the flange is beveled to mate with the slopingshoulder 27 of the bore 21. When seated on the shoulder 27, the flangeis adapted to close the inlet opening 28.

The valve stem 45 has a normal closed position shown in FIG. 2 in whichthe inlet port 47 is out of the fluid chamber 38 and is sealed closed bythe primary sealing member or ring 36. In this closed position, theflange 50 is engaged against the ring 36 and the slot 49 is spaced fromthe sealing ring 37 with the chamber 38. The valve stem 45 is urged intothe closed position by a coil spring 55 which is disposed around thevalve stem between the flange 50 and the sealing ring 37 The valve stem45 is movable from the closed position into two operative positionswherein the inlet port 47 is in the fluid chamber 38 and is incommunication with either the inlet opening 28 or the lower opening 22of the bore 21. In the first operative position shown in FIG. 3, theflange 50 is spaced between the ring 36 and the inlet opening 28, Aswill be apparent, fluid entering the chamber 38 is free to flow throughthe flange passage 51 and into the inlet port 47 of the valve stemoutlet passage 46. Further inward movement of the valve stem 45 iseflective to place the stem in its second operative position (FIG. 3)wherein the beveled surface 52 of the flange 50 is seated on theshoulder 27 so as to close the valve body inlet opening 28. In thissecond operative position, the slot 49 extends from the fluid chamber 38past the sealing ring 37. Thus fluid is permitted to flow into the lowerend of the bore 21, past the sealing ring 37 into the chamber 38, andthen through the flange passage 52 into the inlet port 47 of the outletpassage 46.

When the valve stem 45 is held in its closed position by the spring 55as shown in FIG. 2, the primary sealing ring 36 closes the inlet port 47so as to form a positive seal against the escape of gaseous propellantthrough the valve. At the same time, the engagement of the flange 50against the inner surface of the ring 36 cooperates to prevent thepropellant from escaping from around the valve stem. Thus, the describedstructure achieves the objective of a simplified and effective positiveseal for preventing escape of both the propellant and the product.

OPERATION When the can 11 is in an upright position, the valve stem 45may be fully depressed to the position shown in FIG. 4. When the valvestem is fully depressed, the valve 10 is in a product-dischargeposition. The inlet opening 28 is closed by the flange 50 and the slot49 provides communication between the lower end opening 22 of the boreand the chamber 38. Thus, the liquid product is forced up the dip tube23 by the pressure of of the gaseous propellant and throughthe opening22 into the lower end of the valve body 20. The liquid product flows inthe slot 49 past the secondary sealing member 37 into the chamber 38 andthen through the flange passage 51 into the inlet port 47 of the valvestem. The liquid product flows through the central outlet passage 46 andis discharged from the outlet 48 into the atmosphere.

To clean the discharge outlet 48 after each use of the can 11 in anupright position, the valve stem is permitted to move axially outwardlyuntil it is in the position of FIG. 3. The inlet 28 is open in thiscleaning position, while the bore opening 22 is sealed from the fluidchamber 38 by the ring 37. Thus, the gaseous propellant can pass intothe chamber 38 through the inlet 28 and through the flange passage 51into inlet port 47 of the central valve stem passage 46. Passing of thepropellant through the outlet passage 46 tends to blow away and disperseany residue of the liquid product which may remain within the outletport 48.

When the desired amount ofpropellant has been released so that thepassage 46 and the outlet 48 are sufficiently cleared, the valve stem 45is fully released until it again assumes the closed position of FIG. 2.As explained above, the valve mechanism is fully closed in this positionso that escape of the gaseous propellant is prevented when the can isnot in use.

When a container 11 is used in an inverted position, the product flowsto the end of the can around the valve 10 and the gaseous propellant iscaused to rise to the opposite end of the can around the distal end ofthe dip tube 23. In order to discharge the liquid product with the canin an inverted position, the valve stem is partially depressed to theposition shown in FIG. 3. In this position the liquid product is forcedthrough the inlet opening 28 into the chamber 38, through the flangepassage 51, and into the inlet port 47 of the valve stem passage 46. Theliquid product is discharged into the atmosphere through the valve stempassage 46 and the outlet 48. Thus, in an inverted position of the can11, partially depressing the valve stem 45 is effective to discharge theliquid product into the atmosphere.

When the valve stem is fully depressed with the can in an invertedposition, a quantity of propellant can be released to purge the valvestem passage 45. The valve body inlet 28 is closed to prevent the liquidproduct from entering the chamber 38, while the slot 49 is positioned toby-pass the ring 37. Thus, the propellant flows through the dip tube 23,into the chamber 38, through the flange passage 51, and into the valvestem passage 46 where the propellant is discharged through the outlet48. This method of cleaning is not as effective as that previouslydescribed, however, since it may require a substantial amount of theliquid product to be expelled from the dip tube and the chamber 38. Thepreferred way of cleaning the valve after using the can in an invertedposition is to place the can in an upright position so that a quantityof the propellant may be released as described above in conjunction withFIG. 3.

Although the invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and the scope of the invention as hereinafterclaimed.

What is claimed is:

1. A valve mechanism adapted to be used in combination with apressurized container, said valve mechanism comprising:

(a) a valve body member having an internal chamber and first and secondspaced inlet openings into said chamber,

(b) a movable operating member extending into said chamber, saidoperating member having an outlet passage extending from an inlet portto an outlet p (c) said operating member being movable between a closedposition of said inlet port and first and second positions wherein saidinlet port communicates with said first and second inlet openings,respectively,

(d) primary sealing means coactablewith said operating member to preventthe escape of fluid under pressure from between said members and to sealsaid inlet port in said closed position,

(e) one of said members including secondary sealing means spaced fromsaid primary sealing means and operatively disposed between said inletport and said second inlet opening, said secondary sealing means beingcoactable with the other of said members in said closed and firstpositions to prevent the flow of fluid through said second inlet openingand into said chamber,

(f) said other of said members including a by-pass passage to permitfluid flow from second inlet opening past said secondary sealing meanswhen said operating member is in said second position, and,

(g) means carried by one of said members and coactable with the other ofsaid members to block fluid flow between said first inlet opening andsaid inlet port when said operating member is in said second position.

2. The valve mechanism as claimed in claim 1 wherein said means ofparagraph (g) is carried by said operating member and is disposedbetween said sealing means within said chamber.

3. The valve mechanism as claimed in claim 1 wherein said secondarysealing means is carried by said body member, and wherein said by-passpassage is formed in said operating member.

4. A valve mechanism adapted to be used in combination with apressurized container, said valve mechanism comprising:

(a) a valve body member having a bore,

(b) a movable operating member extending within said bore, saidoperating member including an outlet passage extending from an inletport to an outlet port,

(c) spaced apart, primary and secondary sealing means coactable betweensaid members to define a fluid chamber within said bore,

(d) said body member including an inlet opening into said chamber,

(e) said operating member being movable between:

(i) a closed position wherein fluid communication between said inletopening and said inlet port is blocked by said primary sealing means,

(ii) a second position wherein said inlet opening and said inlet portare in fluid communication, and,

(iii) a third position,

(f) means carried by one of said members and coactable with the other ofsaid members to block fluid flow between said inlet opening and saidinlet port when said operating member is in said third position, and

(g) one of said members including an inlet passage providing fluidcommunication into said chamber when said operating member is in saidthird position.

5. A valve mechanism adapted to be used in combination with apressurized container, said valve mechanism comprising:

(a) a valve body member having a chamber and a first inlet opening intosaid chamber,

(b) a movable operating member extending into body member, saidoperating member including an outlet passage extending from an inletport to an outlet port, 1

(c) one of said members being formed to define a second inlet openinginto said valve body chamber,

(d) primary sealing means carried by said body member, said primarysealing means being coactable with said operating member to preventescape of pressurized fluid therebetween and to block fluid flow betweensaid first inlet opening and said inlet port in a closed position ofsaid operating member,

(e) said operating member being movable from said closed position tofirst and second positions wherein said inlet port is within said valvebody chamber,

(f) secondary sealing means coactable between said members, saidsecondary sealing means cooperating with said one member to close saidsecond inlet opening in said closed and first positions and to permitfluid flow into said chamber through said second inlet opening in saidsecond position, and,

(g) means carried by one of said members for closing said first inletopening in said second position.

6. A valve mechanism adapted to be used in combination with apressurized container, said valve mechanism comprising:

(a) a valve body member having a through bore and first and secondspaced inlet openings into said bore,

(b) a valve stem member reciprocable in said bore, said valve stemmember having an outlet passage extending from an inlet port to anoutlet port,

(c) primary sealing means carried by said body member, said primarysealing means coacting with said stem member to prevent escape ofpressurized fluid therebetween and to seal said inlet port in a closedposition of said stem member,

(d) secondary sealing means carried by one of said members in spacedrelation to said primary sealing means to define a fluid chamber in saidbore, said secondary sealing means being coactable with the other ofsaid members to prevent fluid flow through said second inlet openinginto said chamber in first and second positions of said stem member,

(c) said other of said members including an inlet passage extendingbetween said second inlet opening and said fluid chamber when saidoperating member is moved to said second position, and,

(f) means carried by one of said members and coacting with the other ofsaid members to seal said inlet port from said first inlet opening whensaid stem member is in said second position.

7. A valve mechanism adapted to be used in combination with apressurized container, said valve mechanism comprising:

(a) a valve body member having a through bore and first and secondspaced inlet openings into said bore;

(b) a valve stem member reciprocable in said bore,

said valve stem member having an outlet passage extending from an inletport to an outlet port;

() primary sealing means carried by said body member, said primarysealing means coacting with said stem member to prevent escape ofpressurized fluid therebetween and to seal said inlet port in a closedposition of said stem member;

(d) secondary sealing means carried by one of said members in spacedrelation to said primary sealing means to define a fluid chamber in saidbore, said secondary sealing means being coactable with the other ofsaid members to prevent fluid flow through said second inlet openinginto said chamber in first and second positions of said stem member;

(e) said other of said members including an inlet passage extendingbetween said second inlet opening and said fluid chamber when saidoperating member is moved to said second position;

(f) means carried by one of said members and coacting with the other ofsaid members to seal said inlet port from said first inlet opening whensaid stern member is in said second position; and,

g) said means carried by one of said members comprising a flange on saidstem member in wiping engagement with the wall of said bore, said flangehaving a passageway opening on opposite faces to provide fluidcommunication between said first inlet opening and said inlet port whensaid stem member is in said first position.

8. The valve mechanism as claimed in claim 7 wherein said secondarysealing means comprises a ring carried by said valve body member, andwherein said inlet passage comprises a slot formed in said stem member.

9. In a liquid dispensing apparatus including a container for a liquidand a gaseous pressurizing agent, the combination with said container ofa valve mechanism comprising:

(a) a hollow valve body projecting into said container, said valve bodyhaving first and second spaced inlet openings communicating with theinside of said container,

(b) a valve stem reciprocable in said valve body, said valve stem havingan inlet passage and an outlet passage, said outlet passage extendingfrom an inlet port to an outlet port venting to the outside of saidcontainer,

(c) a primary sealing member carried by said valve body in peripheralsealing engagement with said valve stem,

((1) a secondary sealing member carried by the valve body within saidbore in peripheral sealing engagement with said valve stem,

(e) said sealing members cooperating to define a fluid chamber in saidbore,

(f) a radially extending flange on said valve stem between said inletport and said inlet passage,

(g) a spring acting on said valve stem to urge it to a closed positionwherein said inlet port is sealed from said fluid chamber,

(h) said valve stem being movable to a first position wherein said inletport is within said chamber and in communication with said first inletopening and to a second position wherein said first inlet opening isclosed by said flange and said inlet passage provides fluidcommunication between said inlet port and said second inlet opening.

10. In a liquid dispensing apparatus including a container for a liquidand a gaseous pressurizing agent, the combination with said container ofa valve mechanism comprising:

(a) a valve body secured to said container, said valve body including abore having an outer end and an inner end, said inner end of said borebeing in communication with the bottom portion of said container,

(b) a first sealing member in the outer end portion of said bore,

(c) a second sealing member mounted within said bore in spaced relationto said first sealing member to define a fluid chamber,

(d) said valve body having an inlet opening communicating between saidchamber and the top portion of said container,

(e) a reciprocable valve stem disposed in said bore and having asubstantially fluid-tight running fit with said sealing members,

(f) said valve stem including an internal passage extending from aninlet port positionable in said chamber and an outlet port ventingoutside of said container, an elongated slot located between said inletport and said inner end of said stem, and means for closing said inletopening in one position of said stem, and

(g) said stem being movable between a closed position wherein said inletport is sealed by said first sealing member, a first position whereinsaid inlet port is within said chamber in communication with said inletopening, and a second position wherein said inlet opening is closed bysaid closing means and said second sealing member is between the ends ofsaid slot, whereby fluid can flow from the lower end of said bore intosaid fluid chamber and said inlet port.

11. The valve mechanism as claimed in claim 10 wherein said closingmeans comprises a radial flange on said valve stem in wiping engagementwith the wall of said bore, said flange having a fluid passage extendingbetween its opposite faces.

12. The valve mechanism as claimed in claim 11 wherein said flange isengageable with said first sealing member in said closed position.

13. The valve mechanism as claimed in claim 12 wherein the wall of saidbore is formed with a shoulder, said inlet opening being located at saidshoulder, and said flange being engageable against said shoulder in saidsecond position.

14. In a liquid dispensing apparatus including a container for liquidand a gaseous pressuring agent, the combination-With said container of avalve mechanism comprising:

(a) a hollow valve body projecting into said container, said valve bodyhaving first and second spaced inlet openings communicating with theinside of said container;

(b) a valve stem reciprocable in said valve body, said valve stem havingan outlet passage extending from an inlet port to an outlet port ventingto the outside of said container;

(0) a three-position valve means operably connected to said valve stem;

(d) said three-position valve means including a means for bringing saidinlet port into communication with the inside of said hollow valve bodywhen said three-position valve is in a second and third position and forpreventing said inlet port from communicating with the inside of saidhollow valve body when said three position valve is in a first position;

(e) said three-position valve means including a means for closing saidfirst spaced inlet opening while said three position valve means is insaid second position; and,

(f) said three-position valve means including a means for closing saidsecond spaced inlet opening while said three-position valve means is insaid third position, I

15. The combination claimed in claim 14 in which said means for closingsaid first spaced inlet opening comprises a radially extendingprojection mounted on said valve stem within said hollow valve body tobe positioned against the inside of said hollow valve body over saidfirst spaced inlet opening while said valve stem is in a second positionand to be positioned away from said first spaced inlet while said valvestem is in a first and a third position, said first, second, and thirdpositions of said valve stem corresponding to said first, second, andthird positions of said three position valve.

16. The combination of claim 15 in which said projection comprises aradially extending flange mounted on said valve stem to be in wipingengagement with the inside wall of said hollow valve body.

References Cited by the Examiner UNITED STATES PATENTS 10 RAPHAEL M.LUPO, Primary Examiner.

14. IN A LIQUID DISPENSING APPARATUS INCLUDING A CONTAINER FOR LIQUIDAND A GASEOUS PRESSURING AGENT, THE COMBINATION WITH SAID CONTAINER OF AVALVE MECHANISM COMPRISING: (A) A HOLLOW VALVE BODY PROJECTING INTO SAIDCONTAINER, SAID VALVE BODY HAVING FIRST AND SECOND SPACED INLET OPENINGSCOMMUNICATING WITH THE INSIDE OF SAID CONTAINER; (B) A VALVE STEMRECIPROCABLE IN SAID VALVE BODY, SAID VALVE STEM HAVING AN OUTLETPASSAGE EXTENDING FROM AN INLET PORT TO AN OUTLET PORT VENTING TO THEOUTSIDE OF SAID CONTAINER; (C) A THREE-POSITION VALVE MEANS OPERABLYCONNECTED TO SAID VALVE STEM; (D) SAID THREE-POSITION VALVE MEANSINCLUDING A MEANS FOR BRINGING SAID INLET PORT INTO COMMUNICATION WITHTHE INSIDE OF SAID HOLLOW VALVE BODY WHEN SAID THREE-POSITION VALVE ISIN A SECOND AND THIRD POSITION AND FOR PREVENTING SAID INLET PORT FROMCOMMUNICATING WITH THE INSIDE OF SAID HOLLOW VALVE BODY WHEN SAID THREEPOSITION VALVE IS IN A FIRST POSITION; (E) AND THREE-POSITION VALVEMEANS INCLUDING A MEANS FOR CLOSING SAID FIRST SPACED INLET OPENINGWHILE SAID THREE POSITION VALVE MEANS IS IN SAID SECOND POSITION; AND(F) SAID THREE-POSITION VALVE MEANS INCLUDING A MEANS FOR CLOSING SAIDSECOND SPACED INLET OPENING WHILE SAID THREE-POSITION VALVE MEANS IS INSAID THIRD POSITION.